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Title: Contributions to cosmic reionization from dark matter annihilation and decay

Dark matter annihilation or decay could have a significant impact on the ionization and thermal history of the universe. In this paper, we study the potential contribution of dark matter annihilation (s-wave- or p-wave-dominated) or decay to cosmic reionization, via the production of electrons, positrons and photons. We map out the possible perturbations to the ionization and thermal histories of the universe due to dark matter processes, over a broad range of velocity-averaged annihilation cross sections/decay lifetimes and dark matter masses. We have employed recent numerical studies of the efficiency with which annihilation/decay products induce heating and ionization in the intergalactic medium, and in this work extended them down to a redshift of 1 + z = 4 for two different reionization scenarios.We also improve on earlier studies by using the results of detailed structure formation models of dark matter haloes and subhaloes that are consistent with up-to-date N-body simulations, with estimates on the uncertainties that originate from the smallest scales.We find that for dark matter models that are consistent with experimental constraints, a contribution of more than 10% to the ionization fraction at reionization is disallowed for all annihilation scenarios. Such a contribution is possible only for decays intomore » electron/positron pairs, for light dark matter with mass m χ ≲ 100 MeV, and a decay lifetime τ χ ~ 10 24–10 25 s.« less
Authors:
 [1] ;  [1] ;  [2]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Univ. of Copenhagen (Denmark). The Niels Bohr Inst.
Publication Date:
Grant/Contract Number:
SC0013999; SC00012567; PIIF-GA-2013-62772
Type:
Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 94; Journal Issue: 6; Journal ID: ISSN 2470-0010
Publisher:
American Physical Society (APS)
Research Org:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS
OSTI Identifier:
1505799
Alternate Identifier(s):
OSTI ID: 1322444

Liu, Hongwan, Slatyer, Tracy R., and Zavala, Jesús. Contributions to cosmic reionization from dark matter annihilation and decay. United States: N. p., Web. doi:10.1103/physrevd.94.063507.
Liu, Hongwan, Slatyer, Tracy R., & Zavala, Jesús. Contributions to cosmic reionization from dark matter annihilation and decay. United States. doi:10.1103/physrevd.94.063507.
Liu, Hongwan, Slatyer, Tracy R., and Zavala, Jesús. 2016. "Contributions to cosmic reionization from dark matter annihilation and decay". United States. doi:10.1103/physrevd.94.063507. https://www.osti.gov/servlets/purl/1505799.
@article{osti_1505799,
title = {Contributions to cosmic reionization from dark matter annihilation and decay},
author = {Liu, Hongwan and Slatyer, Tracy R. and Zavala, Jesús},
abstractNote = {Dark matter annihilation or decay could have a significant impact on the ionization and thermal history of the universe. In this paper, we study the potential contribution of dark matter annihilation (s-wave- or p-wave-dominated) or decay to cosmic reionization, via the production of electrons, positrons and photons. We map out the possible perturbations to the ionization and thermal histories of the universe due to dark matter processes, over a broad range of velocity-averaged annihilation cross sections/decay lifetimes and dark matter masses. We have employed recent numerical studies of the efficiency with which annihilation/decay products induce heating and ionization in the intergalactic medium, and in this work extended them down to a redshift of 1 + z = 4 for two different reionization scenarios.We also improve on earlier studies by using the results of detailed structure formation models of dark matter haloes and subhaloes that are consistent with up-to-date N-body simulations, with estimates on the uncertainties that originate from the smallest scales.We find that for dark matter models that are consistent with experimental constraints, a contribution of more than 10% to the ionization fraction at reionization is disallowed for all annihilation scenarios. Such a contribution is possible only for decays into electron/positron pairs, for light dark matter with mass mχ ≲ 100 MeV, and a decay lifetime τχ ~ 1024–1025 s.},
doi = {10.1103/physrevd.94.063507},
journal = {Physical Review D},
number = 6,
volume = 94,
place = {United States},
year = {2016},
month = {9}
}